This invention relates to an improved method for mounting a generally cylindrical tank in a precast or preformed, generally congruent shaped half shell.
In U.S. Pat. No. 5,033,638 entitled "Above Ground Hazardous Liquid Storage Apparatus," there is disclosed a liquid storage tank construction comprised of a supportive, precast, outer lower half shell which receives and retains a separate internal cylindrical steel tank for storing liquids. The precast, outer half shell is combined with a generally mirror image, upper half shell that covers the tank. The half shells both include internal ribs which support and locate the cylindrical tank and maintain it in a generally fixed position spaced from the interior walls of the half shells.
The half shells are typically constructed from a reinforced concrete material. The lower half shell in combination with the upper half shell thus defines a vault for a tank. The vault retains fluid which might be leaking from the tank. In this manner, leakage from the tank into the environment is precluded. Consequently, the tank, which may contain hazardous materials, can be easily stored above ground where it is protected by the concrete shell from environmental hazard and other hazards which might impact on the tank, but where it is easily inspected and accessible for replacement or repair.
During the fabrication of such apparatus, it is necessary to appropriately align the tank on the support ribs within the lower half shell. Because the tolerances associated with the materials comprising the half shells are quite different from those associated with the storage tank, there may be a significant dimensional difference between the support ribs of the lower half shell and the tank. Thus, merely lowering the steel tank onto the ribs within the lower half shell may not satisfactorily position the tank within that half shell. Consequently, there has developed a need for a device and a process by which the cylindrical tank may be appropriately and properly positioned within the lower half shell so that the upper half shell may be properly placed over and mated with the lower half shell to effectively and efficiently protect the internal steel tank.